The Japanese patent application JP H04 22767 A has disclosed a pressure generator, referred to as a hydraulic plunger pump, with a ball screw drive and a piston-cylinder unit. The ball screw drive has a spindle nut which can be driven in rotation by means of an electric motor and which thus axially moves a spindle, which in turn moves a piston in a cylinder of the piston-cylinder unit. In one embodiment, the spindle nut is driven in rotation directly by way of a coaxially arranged electric hollow-shaft motor which surrounds the ball screw drive, and in another embodiment, by way of an electric motor, which is arranged axially parallel and adjacent to the helical gearing, via a spur gear mechanism.